Train-control system



Sept. 2*, 1930. P, x. m5 1,775,051

TRAIN common SYSTEI Filed ma 21, 1924 Patented Sept. 2, 1930 UNITED STATES PATENT orFicE PHILIP X. RICE, OF DA NVILLE, ILLINOIS, ASSIGNOE TO THE MILLER TRAIN CONTROL CORPORATION, OF STAUNTON, VIRGINIA, A CORPORATION OF VIRGINIA TRAIN-CONTROL SYSTEM Application filed May 21,

This invention relates to train control sys tems, and more particularly to an alternating current induction train control system.

In the present invention, 1 provide a nor- 5 mally energized engine magnet to retain a control valve in closed position. I further provide track elements at spaced intervals on the track-way, which elements have circuits normally resonant at the frequency employed in the vehicle magnet, but when the track elements are de-tuned, due to an open circuit condition in the track-way, they act as interceptors of the energy normaly delivered to the magnet and permit the valve to open.

In the present invention, I provide a receiver carried by the vehicle consisting of two parts, one being a primary coil and the other a secondary, whereby greater sensitiveness to the presence or absence of iron bodies in the path of the receiver may be obtained.

An object of the invention is the provision of a train control system of the induction type, which is reliable in operation, in which there is no possibility of obtaining false clear signals,and at the same time, which is so sensitive to track elements that the receiver may be carried at a convenient height above the roadway apparatus.

In the accompanying drawings, I have shown one embodiment of theinvention. In

this showing:

Figure 1 is a diagrammatic view of the apparatus carried by the train or locomotive,

Figure 2 is a diagrammatic view of the locomotive circuits in normal condition,

Figure 3 is a similar View showing the secondary coil ofthe locomotive circuit detuned by an open circuited track element,

Figure 4 is a diagrammatic view of a track 40 element showing the connections to the track element and relay, and, c

Figure 5 is a modification thereof.

Referring to the drawings, the reference numeral 1 designates a primary receiver which may be constructed in any suitable manner and. provided with windings 2. A secondary receiver 3 is arranged in proximity to the primary receiver and the secondary receiver is provided with windings e Alternating current generator means of any de- 1924. Serial N0. 714,962.

sired type 4: is provided with suitable lead ires 5 and 6, and these wires preferably have a potential difierence of 32 volts and furnish all. the current for the automatic stop apparatus on the engine and for the track elements when the latter are in clear condition. A third Wire 7 may be connected to the generator if desired, but this wire is not essential. The wire 7 does not carry power or currentsupplied by the generator, but carries power or current induced from the primaryv receiver into the secondary receiver through a portion of the generator, the voltage induced in the secondary receiver being opposed by a portion oi the generator voltage. As illustrated, this wire 7 is connected. to an additional slip ring 7* on the generator so that the voltage between the wire 7 and the lead wire 5 is a selected portion of the entire generator voltage and is sullicient to reduce the voltage at the terminals of the secondary receiver but is less than the voltage induced in said secondary receiver from the primary receiver. Assuming the total generator voltage to be 32 volts as indicated, the portion of the generator voltage impressed across the wires 5 and 7 may be about 16 volts, this portion of the generator voltage bein preterably of a value insufficient to energize the valve control magnets to keep the valve closed, in the event that the induced voltage in the coils of the secondary receiver should fail. It is assumed for purposes of illustration, that the voltage normally induced in the coils of the secondary receiver will be about 40 volts so that the net voltage supplying current to the valve control magnet 14: will be 4016, or 24k volts. When the car element or receiver is over a trackelement in its stopping condition, the voltage induced in the coils of the secondary receiver is greatly educed, to about 25 volts, so that the net voltage applied to the valve control magnet 14 becomes only about 9 volts. Vi ith these assumed values, it can be seen that he voltage induced in the coils of the secondary receiver is changed from 40 to 25 by the action of the track element, representing a reduction of 37 per cent; whereas the voltage impressed on the valve control magnets 14 change in induced voltage in the coils of the secondary receiver, caused by the action of a track element in its stopping condition, is accompanied by a greater percentage change in the voltage on the magnet coils '14, so

that said magnet coils are more effectively deenergized than they would be if the wire 7 were connected to the wire 5 and no portion of the generator voltage were included in the circuit through the coils of the secondary receiver. Various ways of obtaining different impressed voltages acrossthe wires 5 and 6 and 5 and 7 may be employed, and the illustration of a generator with an extra slip ring 7 is merely illustrative. Under normal conditions, current is furnished to the primary receiver through a resonant circuit. The wire 5 passes to a terminal 18 which'in turn is connected to the receiver 1, as shown. From the receiver, a wire 8 leads to a primary condenser 9 and the primary condenser 9 is connected to the wire 6, by a connection 10. The current flowing through the primary receiver is an exciting current and secondary voltage is generated in the secondary receiver 3, due to the primary flux threading the secondary coil. As shown in Figure 2 of the drawings, the flux from the primary receiver flows through the secondary receiver, as indicated at 11. One end of the secondary coil is provided with a lead wire 12, connected to a wire 13 leading to an electro-responsive device,14 which is biased to open position and connected to a control valve. The device 14 when energized, holds the valve (not shown) in closed position. From the electroresponsive device secondary current flows through a wire 15, which is connected to the wire '5. The secondary current continues through the generator 7 to wire 7, thence through a secondary condenser 16. This condenser normally neutralizes the inductive reactance of the secondary circuit, and also normally loads the primary by electro-1nagnetio inductive coupling. Both the primary condenser and the secondary condenser should be provided with exact capacities adapted in combination, but not individually, to no anally encourage vigorous primary current and flux. From the secondary condenser, a wire 17 leads back to the receiver 3. I further provide a reset circuitirom the point 18 where the wires 5. and 15 are connected, through the electro-responsive device '14 and'wire 13 to contacts19 of'a re-set governor 20. From the governor, there is provided a lead wire 21 connected to a re-" setcondenser 22 which is adapted to neutralize the inductive reactance of the valve magnet and provides absolute protection against false release, due to possible crosses or grounds. The condenser 22 is connected to a Wire 23, which is connected to a push butposition. oil or decreased in a sufiicient amount, the

ton 24 and the push button 24 is connected to the generator wire 6 by a connection 25.

In Figures 4 and 5 of the drawings, there is shown a construction of track element adapted to be used in connection with the apparatus described. elements are formed of a. plate of magnetic material 26 having recesses 27 formed therein. Coils 28 are arranged in these recesses. A relay 29 is controlled by the usual track relay (not shown) and this relay 29 is provided with a plurality of contacts 30 equal in numher to the number of coils 28. The contacts are adapted to close circuits through lead wires 31 connected to the coils and the opposite ends of the coils are'connected to a common return wire 32 by suitable connections 33. The return wire is inturn connected to the contacts 30 by a wire 33 and connections 34, and condensers 35 are arranged in these connections. In Figure 5 of the drawings, the coils 28 are connected in pairs. As shown, the coil at the left is connected to the third coil by a wire 36 which is provided with a connection 3? extending toone of t 1e movable contacts 30. The common return wire 32 is connected to the end coils'by connections 38 and is not connected to the other coil paired with the left hand end coil. Similarly, the second and fourth coils are connected to eachother by a wire 39 and the fourth coil is provided with a wire 40 similar tothe wire 37. The second coilis connected to the-common return wire 32 by a wire 41. The coil 28 at the right is connected directly to the' other movable contact by means of wires 42 portion of the flux flowing from the primary receiver to the track element, as indicated at 44. In addition, the primary receiver is de-tuned by the proximity of the track element and the total amount of primary flux decreased thereby. The leakage flu from the secondary receiver is also attracted by the track element, as indicated at 45, and this attraction is augmented progressively but practically instantaneously by the-de tuning efiect of the track element on the loaded secondary circuit.

The operation of the system will be apparent it'rom the foregoing description. :As shown in Figure 20f the drawings, the primary receiver'is furnished withan exciting current from the generator througha reso nant circuit. The secondary energy normally energizes the electro-responsive device 14 to retain the valve (not shown) in closed If this secondary current is out As shown, "the track device 14 becomes deenergized and the valve opens. As previously explained, the proximity of the dead track element to the receiver intercepts a portion of the primary flux and diverts it from the secondary core thus decreasing the secondary current and deenerv gizing the device 14 to open the valve. The total amount of primary flux is also decreased, constituting a second assurance that the train will be stopped and the leakage flux from the secondary receiver is augmented by the ale-tuning effect of the track element on the loaded secondary circuit, which is a third assurance that the train will respond to the stopping indication. When the secondary circuit has its normal reactance and system resonance interrupted by the proximity of the low reluctance track element, the primary current decreases to a remarkable extent. This extra reduction of primary current is determined, notby the primary circuit characteristics alone, but by the mutual coupling and reflex action of the properly designed secondary circuit of correct capacity. H the secondary had no condenser or it the secondary tuning were not properly co-ordinated with the primary circuit, such great sensitivity would not be attainable.

It will be noted that any combination of crosses, grounds, or open circuits will either de-tune the normally resonant circuits or will entirely interrupt the secondary current. It is thus impossible to have a false clear signal or a false re-set, due to accidents to the circuits on the locomotive.

V] hen a dead track element is encountered, the contacts are retained in open position due to the fact that the ramp relay 29 is deenergized. The flux of the primary receiver 1 is then diverted from the secondary receiver to the coils 28 of the track element. Flux flows longitud'nally through the track element coils until the other end of the primary receiver is approached, at which point the flux leaves the track element and returns to the primary receiver. Any magnetic force remaining in the secondary receiver is also directed toward the track element. The track element also de-tunes both primary and secondary circuits on the locomotive. As a result of these several causes very little flux is produced by the receiver while over a dead track element and a surpisingly small mount of iron in the track element sufiices to stop the train.

If the tuned track element circuits are closed at the relay, such small amount of flux; as does reach the track element is reflected back into the receiver by the resonance of the condensers so that the valve armature is held as securely or more securely than under 'normal'conditio-ns where the receiver is not over a track element. In other words,the closed track element circuits generate counter-magnetomotive force opposing the cyclic produces it.

change in flux from primary to track element in the same manner that any short circuited coil of a transformer would do. A slight charging current introduced in the track element circuits when closed is returned from the condensers to the receiver periodically during each cycle.

The condensers employed in the track element circuitshould not be of such capacity to provide exact resonance. The amount of capacity must be selected in accordance with the intended control of the track element on the progress of the vehicle. If the track element is intended to permit the vehicle to pass without restriction, the traflic controlled condenser 35 of the track element must have a capacity reactance less than the inductive reactance of the track element circuit. If the track element is in condition to stop the vehicle, the capacity reactance must exceed the inductive reactance. The phase angle effects of the system will be apparent when itis considered that when the cores 1 and 3 are over an open circuited track element, the secondary core and coils 3 and 4 receive fluxes from two sources more or less in phase. The normal flux ll continues, in reduced quantity, and a fl is sent up to the secondary from the track element core 26. The flux lf) is the net result of current oscillating aetween coils 28 and condenser 35, and this current will flow early or late according to whether there is a predominance of capacity reactance or inductive reactance. At exact resonance, i. e., if the condenser reactance and the inductive reactancewere equal, the current would have its peak value in phase with its driving electro-motive force in coils 4, but this E. M. F. displaced in phase from the flux which 7 In that case the returned llLlX l5 would be out of phase with the normal flu): 11 by 90, and the net result would be negligible. If the magneto-motive force corresponding to flux 45 be made to occur earlier, as when the track element capaci y reactance predominates, one component of magnetomotive force 45 will attract the remaining normal flux 11- d w wardly into the track element, and secondary coils 4 will receive no net flux and the vehicle will be stopped with great reliability. If the inductance pre dominates, as when. a low reactant-e condenser is employed for proceed indication, the flux 45 will arrive at the secondary region at approximately the same time the flux 11 reaches the secondary region, and t ins secondary coils are energized strongly and the valve magnet 14 is retained as strongly or more strongly than under normal condition.

It will be apparent that the current supplied to the magnet 14- is sufficient to re A the valve in closed condition, but the CH1? 0 is insufficient for resetting the valve after the latter has been opened, due to the inductive reactance of the magnet 14:. As previously stated, I provide in. the reset circuit a capacity 22 the reactance of which is adapted to neutralize or balance out the inductive reactance oi the valve magnets. Accordingly, after a stop indication has been given, the valve magnets may be energized to reset the valve by closing the switch 24., the completion of the circuit, however, being dependent upon the speed of the vehicle since the arms of the governor must close the circuit across the contacts 19. 7

It is to be understood that the'l orm of my invention herewith shown and described is to be taken as a preferred example of the same,

and that various changes inthe shape, size,

and arrangement of parts may be resorted to Without departing from the spirit of the invention or the scope of the subjoined claims.

I claim: 1. In a system of train control, a source of alternating current arranged on the vehicle,

a primary magnet coil continuously energized being connected to each other in normally closed circuits, and movable contacts arranged in said circuitsto permit the circuits of said coils to be closed. V

2. In a system of train control, a primary magnet coil continuouslyenergized by alternativ current, a secondary coil mutually coupled thereto by mutual inductance, acon-r V trol circuit connected to said secondary coil,

a track element including a magnetizable core and coils wound on said core, said track element acting to divert flux produced by the primary coil from the secondary coil, and a circuit for said last, named coils, said last named circuit including inductance and capacity adapted to control the magnitude of said diverted flux.

in a s stem of train control a orimar magnet coil continuously energized by alternating current, a secondary coil coupled thereto by inductance, a control circuit connectedto said secondary coil, and trackside 2118 for influencing said coils according to r c .1 ions, said trackside means in ciucing a circuit having capacity reactance and inductive rea'ctance, the capacity resctance being greater than the inductive r-eactance when said trackside means is set rict the progress of the vehicle, and less the inductive reactance when said track side means is set to allow the vehicle to proceed.

at. In an intermittent inductive train control system, a car-carried receiver, comprising primary and secondary cores With primary and secondary coils thereon, said primary and secondary coils being inductlvely responsive device and the secondary coil n'ormally energized by voltage induced in said secondary 0011 from the energized primary coil, andcontrollable means on the track for changing the reluctance of thepartial magnetic circuits through the primary and secondary cores to detune said circuits and also divert primary flux from the secondary coil,

thereby deenergizing the clectro-responsive device When said track means is in its active stopping condition.

5. In a train control system, car-carried circuits respectively including inductively coupled primary and secondary coils, means tuning each of said circuits, a car-carried source of alternating current included in the circuit of the primary coil, said prim ary coil inducing a voltage in the secondary coil, :1, car-carried source of alternating'current voltage in the circuit of the secondary coil opposing, but less than, the induced. voltage in said secondary coil, and traclivvay means for r'educin the induced voltage in said secondary coil. I

6, In a train control system circuits including inductively coupled primary and secondary coils, means for energizing the primary coil With alternating current, means tuning each or said circuits, and a permeable track element positioned to be passed over by the coils, to thereby'detune 'the circuits and divert flux passing from the'prlmary to the secondary coil, coils on the track element,

condensers connected in series with the coils,

and means to make and break the coil circuits. 1

7. In a train control system, circuits ineluding inductively coupled primary and secondary coils, means for energizing the primary coil With alternating current, means tuning each of said circuits, and apermeable track element positioned to be passed over by the coils, to thereby detune the circuits and divert fluxpassing from the primary to the secondary coil, control member in the secondary circuit, and a source of electronormally induced in the secondarycoil.

8. In a train control system, gcircuitsi inc cluding inductively coupled primary and secondary coils, means for energizing the primary coil .vvith alterna Uingcurrent, means tuning each of saidcircuits, and a permeable track element positioned to be passedjover' by the coils, to thereby detune the c1rcuits secondary circuit, and a source of electromotive force of constant value in the secondary circuit opposed to, but less than, the electro-motive force normally induced in the secondary coil.

9. In a train control system, a control member, a control circuit including the member, two opposing sources of electro-motive force in the circuit normally effective to cause enough current to flow to energize the control member, and means controlled by traflic conditions for decreasing the predominating electro-motive force to cause deenergization of the control member, the electro-motive force which does not predominate being supplied from an alternating current source and being substantially constant in amount.

10. In a train control system, a control member, a control circuit including the member, two opposing sources of electro-motive force in the circuit normally effective to cause enough current to flow to energize the control member, and means controlled by traffic conditions for decreasing the predominating electro-motive force to cause deenergization of the control member, the electro-motive force which does not predominate being supplied from an alternating current source and being substantially constant in amount, and unaffected by traffic conditions.

11. In a train control system, a control member, a control circuit including the member, two opposing sources of electro-motive force in the circuit normally effective to cause enough current to flow to energize the control member, and means controlled by traffic conditions for decreasing the predominating electro-motive force to cause deenergization of the control member, the electro-motive force which does not predominate being supplied from an alternating current source and being substantially constant in amount, whereby a given per cent. decrease in the predominating electro-motive force causes a larger per cent. decrease in the combined electro-motive force in the circuit to thus increase the sensitivity of the system.

In testimony whereof, I afiiX my signature.

7 PHILIP X. RICE. 

